You religiously close apps and obviously have issues with safari crashing, I don't touch the running apps and have no problems with safari whatsoever. What does this tell us? Probably nothing except that you're running 64bit IOSand I'm not, and 64bit safari has problems which are completely unrelated to this thread.
The memory leakage is more consistent in 64-bit version of iOS 7, but not only in that ...
You probably are the only one not having memory problems with Safari and ram ... I mean the only one in the world